#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <cstdio>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/epoll.h>
#include <pthread.h>
#include <cassert>
#include <pthread.h>
#define MAX_EVENT_NUMBER 1024
#define BUFFER_SIZE 1024
struct fds
{
    int epollfd;
    int sockfd;
};

int SetNonBlocking(int fd)
{
    int old_option = fcntl(fd, F_GETFL);
    int new_option = old_option | O_NONBLOCK;
    fcntl(fd, F_SETFL, new_option);
    return old_option;
}

void AddFd(int epollfd, int fd, bool oneshot)
{
    epoll_event event;
    event.data.fd = fd;
    event.events = EPOLLIN;
    if (oneshot)
    {
        event.events |= EPOLLONESHOT;
    }
    epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &event);
    SetNonBlocking(fd);
}

void reset_oneshot(int epollfd, int fd)
{
    epoll_event event;
    event.data.fd = fd;
    event.events = EPOLLIN | EPOLLOUT | EPOLLONESHOT;
    epoll_ctl(epollfd, EPOLL_CTL_MOD, fd, &event);
}

void *worker(void *arg)
{
    fds *self = (fds *)arg;
    int sockfd = self->sockfd;
    int epollfd = self->epollfd;
    printf("开启一个新的线程去接收文件描述符：%d上的数据\n", sockfd);
    char buf[BUFFER_SIZE] = {0};
    while (1)
    {
        int ret = recv(sockfd, buf, BUFFER_SIZE - 1, 0);
        if (ret == 0)
        {
            close(sockfd);
            printf("外面已经关闭了链接\n");
            break;
        }
        else if (ret < 0)
        {
            if (errno == EAGAIN)
            {
                reset_oneshot(epollfd, sockfd);
                printf("读取完毕！\n");
                break;
            }
        }
        else
        {
            printf("得到的数据是：%s,正在处理数据...\n", buf);
            sleep(5);
        }
    }
    printf("线程结束接收在文件描述符：%d上的数据\n", sockfd);
    return nullptr;
}

int main(int argc, char **argv)
{
    if (argc <= 2)
    {
        printf("usage:%s ip_address port_number\n", basename(argv[0]));
        return 1;
    }
    const char *ip = argv[1];
    int port = atoi(argv[2]);
    int ret = 0;
    sockaddr_in address;
    bzero(&address, sizeof(address));
    address.sin_family = AF_INET;
    inet_pton(AF_INET, ip, &address.sin_addr);
    address.sin_port = htons(port);
    int listenfd = socket(AF_INET, SOCK_STREAM, 0);
    assert(listenfd >= 0);
    ret = bind(listenfd, (sockaddr *)&address, sizeof(address));
    assert(ret != -1);
    ret = listen(listenfd, 5);
    assert(ret != -1);
    epoll_event events[MAX_EVENT_NUMBER];
    int epollfd = epoll_create(5);
    assert(epollfd != -1);
    AddFd(epollfd, listenfd, false);
    while (1)
    {
        int ret = epoll_wait(epollfd, events, MAX_EVENT_NUMBER, -1);
        if (ret < 0)
        {
            printf("epoll failure\n");
            break;
        }
        for (int i = 0; i < ret; i++)
        {
            int sockfd = events[i].data.fd;
            if (sockfd == listenfd)
            {
                sockaddr_in client_address;
                socklen_t client_addrlength = sizeof(client_address);
                int connfd = accept(listenfd, (sockaddr *)&client_address, &client_addrlength);
                AddFd(epollfd, connfd, true);
            }
            else if (events[i].events & EPOLLIN)
            {
                pthread_t thread;
                fds fds_for_new_worker;
                fds_for_new_worker.epollfd = epollfd;
                fds_for_new_worker.sockfd = sockfd;
                pthread_create(&thread, nullptr, worker, (void *)&fds_for_new_worker);
            }
            else
            {
                printf("something else happened\n");
            }
        }
    }
    close(listenfd);
    return 0;
}